Revisit old prospects

If you have hardly any leads or prospects on hand why not look into your old price quotations and propositions ? As problems and issues tend to remain it is likely these haven’t got solved and still exist.
Even if another solution has been selected it can be the deployment is not as it should be or as promised during the sales cycle.
There is nothing wrong with showing interest for your prospects as it shows you care about them.

Review meeting

So just call your old prospects and suggest a review meeting in order to find out how the project is moving forward and if you or your company can help. Find out what is missing in the solution currently being implemented.
Moreover you can learn from them about your competitors.
Even if you would only get a minor part of the cake it is better than nothing. In the best case you could win the entire solution if the current solution seems not to bring what was promised.